The Last Day of Her Life

When Sandy Bem found out she had Alzheimer’s, she resolved that before the disease stole her mind, she would kill herself.

The question was, when?

Sandy Bem, a Cornell psychology professor one month shy of her 65th birthday, was alone in her bedroom one night in May 2009, watching an HBO documentary called “The Alzheimer’s Project.” For two years, she had been experiencing what she called “cognitive oddities”: forgetting the names of things or confusing words that sounded similar. She once complained about a “blizzard” on her foot, when she meant a blister; she brought home a bag of plums and, standing in her kitchen, pulled one out and said to a friend: “Is this a plum? I can’t quite seem to fully know.”

Sandy was a small woman, just 4-­foot-­9 and 94 pounds, with an androgynous-­pixie look: cropped hair, glasses and a wardrobe that skewed toward jeans and comfortable sweaters she knit herself in the 1990s. As she watched the documentary, her pulse thrumming in her ears, a woman on screen took a memory test. Sandy decided to take it along with her. Listen to three words, the examiner said, write a sentence of your choice and then try to remember the three words. Sandy heard the three words: “apple,” “table,” “penny.” She wrote a brief sentence: “I was born in Pittsburgh.” She said aloud the words she could remember: “apple,” “penny” . . . . The simplest of memory tests, and she had failed.

The next month, Sandy’s husband, Daryl, from whom she had been amicably separated for 15 years, drove her from Ithaca to the University of Rochester Medical Center for cognitive testing by a neuropsychologist named Mark Mapstone. Mapstone showed Sandy a line drawing and asked her to copy it, and then to draw it from memory 10 minutes later. He read her a list of words and had her recall as many as she could. He gave her two numbers and two letters and asked her to rearrange them in a particular order: low letter, high letter, low number, high number. Thank goodness that last one wasn’t timed, she thought to herself, as she focused all her mental energy on the task. She felt as gleeful as a kid who had earned a gold star when Mapstone said, “Yes, that’s right.”

After three hours, Mapstone gave a preliminary diagnosis: amnestic mild cognitive impairment. At first Sandy was relieved — he had said mild, hadn’t he? — but then she caught the look on his face. This is not a good thing, Mapstone told her gently; most cases of amnestic M.C.I. progress to full-­blown Alzheimer’s disease within 10 years.

When Sandy went back to the waiting room to meet Daryl, she was weeping uncontrollably. Between sobs, she explained the diagnosis and the inevitable decline on the horizon. She felt terror at the prospect of becoming a hollowed-­out person with no memory, mind or sense of identity, as well as fury that she was powerless to do anything but endure it. With Alzheimer’s disease, she would write, it is “extraordinarily difficult for one’s body to die in tandem with the death of one’s self.” That day at Mapstone’s office, she vowed that she would figure out a way to take her own life before the disease took it from her.

Later that month, Sandy sat down in her upstairs study — painted a rich burgundy, as the rest of the house was, to make the sprawling old place feel cozy — and looked at her Mac desktop computer screen. She had some trepidation about her plan to keep a journal of her own deterioration. But she opened a new document, gave it a file name — “Memoir” — and began to type. She tried to describe the maddening capriciousness of “a mind that could be so alive one moment with thought and feeling building toward a next step and then someone erases the blackboard. It’s all gone and I can’t even reconstruct what the topic was. It’s just gone. And I sit with the dark, the blank.”

The prospect of mental decay was particularly painful for Sandy, whose idea of herself was intimately entwined with her ability to think deeply and originally. She was a pioneer in the field of gender studies: She created the Bem Sex Role Inventory in 1974, which assesses a person’s traits along a traditional gender continuum; led Cornell’s fledgling women’s studies program from 1978 to 1985; wrote a groundbreaking book, “The Lenses of Gender,” in 1993; published a memoir, “An Unconventional Family,” in 1998; became a licensed psychotherapist in 2000; and returned for a second term as the director of Cornell’s renamed feminist, gender and sexuality studies program in 2001. Friends and colleagues knew Sandy to be intensely observant, a person who spoke her mind with a bluntness that could be off-­putting. Her best friend, Karen Gilovich, a psychotherapist who lived around the corner, said that one of Sandy’s favorite conversational openers was: “I find myself thinking . . . .” You never knew what would follow. She once wondered aloud, for instance, where the line was between acceptable and unacceptable behavior between parents and their children. Would it automatically be wrong for a waitress who comes home exhausted to ask her young son to rub her feet? Massage her back? Cuddle her? “She was the most clear thinker I have ever seen,” Karen said, “with the ability to cut to the core of any messy issue.”

On June 22, her 65th birthday, Sandy returned to the University of Rochester for another three-­hour consultation. This time it was with a senior neurologist, Charles Duffy, to evaluate not only her cognitive abilities but also her mood and functional status. At one point, Sandy told Duffy she didn’t intend to live out her life with dementia. “I want to live only for as long as I continue to be myself,” she said.

To her surprise, Duffy began to reminisce about his own life. His mother had had Alzheimer’s, he said, and his time nurturing her through her decline profoundly shaped him as a physician, as a researcher and as a man. He said that Sandy — who had spent her career examining and describing her own life with frank insight and clarity — might have a lot to contribute to the world just by experiencing her disease and giving others a glimpse of how it felt to have it.

Sandy was touched by Duffy’s empathy and by his willingness to reveal the private details of his life. Others had stories like his, about people who watch their loved ones slip away, or people who go through that slipping ­away themselves, and are surprised to find a kind of grace in it: the Zen-­like existence in an eternal now, the softening of hard edges, the glorification of simple pleasures. But Sandy knew that wasn’t right for her. Not for a moment was she swayed by Duffy’s arguments.

Over the next several weeks, Sandy told those closest to her about her diagnosis and her plan to end her life before she became incapable of doing so. She told her two adult children, Emily and Jeremy, both in their 30s, and a handful of others: Karen; Daryl’s sister, Robyn Bem; and Sandy’s sister, Bev Lipsitz, who lived in Oregon. No one in that inner circle tried to talk her out of suicide; they knew how fierce she could be once her mind was made up. All they asked was that she promise not to choose a method that would be particularly disturbing — using a gun or jumping off a bridge into one of Ithaca’s famously beautiful gorges. Sandy had contemplated both of those options, but she didn’t want that sort of death either. “What I want,” she typed in her journal in an emphatic boldface font, “is to die on my own timetable and in my own nonviolent way.”

But when would that be? Sandy knew that the Alzheimer’s decline itself was predictable — it usually moves from mild (misplacing things, repeating questions) to moderate (being unable to learn something new, getting lost, failing to recognize loved ones) to severe (losing the ability to speak, swallow or remain continent; needing help with every function of day-­to-­day life). In the immediate aftermath of a diagnosis of amnestic M.C.I., however, she couldn’t know how long each stage might last. She wanted to squeeze in as much intellectual and emotional joy as she could before she died, but she wanted to make sure she didn’t wait too long. She needed to be engaged enough in her life to be able to end it.

In early July, Daryl drove Sandy back to Rochester to see Duffy. The doctor suggested that she start on Namenda, one of the few drugs approved by the F.D.A. to treat Alzheimer’s. Namenda works by increasing the level of glutamate in the brain and is thought to interfere with cell death. Researchers say that by the time someone exhibits mild cognitive impairment, the brain has been degenerating for years, and the drugs, even if they can slow the decline, are too little too late. But doctors and patients hope that starting a drug soon after diagnosis might make a slight but tangible difference — slowing memory loss enough to forestall total dependence. Sandy quickly agreed, which surprised Daryl, because she usually avoided medication, other than a low dose of Prozac that she had been taking for years for depression.

That summer, Daryl began taking her to most of her doctors’ appointments. Sandy could have done the driving herself, but it was good to have Daryl along, so he could recount each visit’s details on the ride home as Sandy took painstaking notes. Besides, she was enjoying Daryl’s company. Something about her diagnosis had opened up an emotional vein in him.

“Who is this wondrous Daryl?” she wrote in her journal that month, after a drive in which Daryl talked with unexpected empathy about Sandy’s early years with a harsh and mercurial mother. She loved the tender, attentive husband who seemed to have emerged from the ruins of her diagnosis. “If some devil had asked whether I would be willing to buy Daryl’s deeper self at the cost of my developing dementia,” she wrote, “I would say NO without hesitation. But it if comes free with my unstoppable decline into hell, I’m thankful for the gift.”

It was a bit like the earliest days of their relationship, back in 1965, when they met at Carnegie Tech in Pittsburgh. She was a senior psychology major; he was a new assistant professor of psychology. Just four months after being introduced by Sandy’s roommate, they married.

They vowed at the time to share everything 50-­50: the housework, the child-rearing, the inevitable career compromises. For a while, this worked well. So well, in fact, that in 1972 they were featured in the inaugural issue of Ms. magazine, in an article titled “A Marriage of Equals.”

The Bems were both psychology professors, at Stanford and then Cornell, and they traveled around the country giving tandem talks about society’s creation of sex-­role stereotypes. They were a slightly odd couple. Sandy was petite and not the least interested in fashion. Daryl was bigger, dapper, six years older and already a bit stooped, with a scholar’s pallor, a kind face and a courtly manner cultivated over his years of performing as a magician. (He would also come to be known, later in his career, for some controversial experiments involving ESP.)

They turned their politics into a way of life, raising their two children, Emily, born in 1974, and Jeremy, born two years later, in what they described as a gender-­neutral way. “Many other feminist couples have experimented with egalitarian relationships and feminist child-rearing,” Sandy wrote in “An Unconventional Family.” But few “have shared the details of their daily lives as exuberantly as Daryl and I.” She talked about everything, in print and on the lecture circuit: letting Jeremy wear pink barrettes to kindergarten; driving Emily past the same construction site every day because a woman was on the crew; hanging a chart on a kitchen cabinet to let the children know which parent was “on duty” that week.

Despite their good intentions, though, the marriage grew strained. As their children went through adolescence, Sandy complained that she felt like a single parent, with Daryl not fully engaging with the family’s needs. They both saw the paradox in their supposedly egalitarian marriage floundering in such a gender-­stereotypical way. In 1994, when the children were 19 and 17, the Bems separated.

After the split, Daryl acted on his attraction to men, a part of his sexuality that he never hid from Sandy. He liked to joke that on their first date, he told her there were three things she should know about him — “I’m a stage magician, I’m from Colorado and I’m primarily homoerotic” — and that she calmly replied that she had never met anyone from Colorado.

About a year after the separation, Daryl began a long-­term relationship with a communications professor at Ithaca College. Yet he and Sandy never divorced, and he remained a frequent visitor to the big house in Cornell Heights where they raised their children. He ate dinner there a few times a week and stayed involved in the lives of Emily and Jeremy — even more involved, in a way, than when he lived with them. He also remained one of Sandy’s best friends and one of her few close confidants. (She had a short-­lived relationship with a woman soon after Daryl moved out and remained single after that.) Daryl wrote in the epilogue to “An Unconventional Family,” which was published four years after they separated, “Sandy and I are still kin.”

On a quiet Friday morning in November 2010, Sandy sat down with a mug of honey-­ginger tea to read two books that Daryl had brought her. By this point, a year and a half after her amnestic M.C.I. diagnosis, she had progressed to what Duffy said was Alzheimer’s disease. She had retired from Cornell, but she was doing well. She could still travel alone to familiar destinations, including Austin, Tex., where Emily was living. Jeremy had temporarily moved back home to be with her. She could read novels, even difficult ones like Cormac McCarthy’s “The Road.” She played tennis, gardened and went for walks around Ithaca with a handful of friends, most of them former colleagues from Cornell. She saw a few psychotherapy patients. One would later say that even though Sandy was having some trouble remembering words, “it didn’t really matter. In a therapy relationship you’re talking more about emotions — and in that regard, she didn’t miss a beat.”

The first book on her table that Friday morning was “Final Exit.” Sandy read it in the early 1990s when it was published; even then she was intrigued by the argument of the author, Derek Humphry, in favor of self-­directed “death with dignity” for people who were terminally ill. The second was a newer book by the Australian right-­to-­die advocatePhilip Nitschke called “The Peaceful Pill Handbook.” The pill in the title (though not literally a pill; it comes in liquid form) was Nembutal, a brand name for pentobarbital, a barbiturate that is used by veterinarians to euthanize animals and that is also used in state-­sanctioned physician-­assisted suicides. After reading about it, Sandy thought pentobarbital was what she was looking for. It was reliable, fast-­acting and — most important to her — a gentle way to die. It causes swift but not sudden unconsciousness and then a gradual slowing of the heart.

There could be complications, of course, like vomiting; Nitschke and his co-­author, Fiona Stewart, recommended taking an anti-nausea drug a few hours before taking the fatal dose to minimize that risk. They warned that pentobarbital is detectable in a person’s body after death — but that didn’t matter to Sandy. In fact, she preferred having people know that she died by her own hand.

One morning during one of Sandy’s frequent phone calls to her sister in Oregon, she told her about the decision to use pentobarbital. Sandy had a special relationship with Bev, who was six years younger. When Sandy married Daryl, Bev was 14, and Sandy invited her sister to live with them rather than with their parents, whose unhappy marriage made it feel, as Sandy put it in her memoir, as if “chaos could erupt at any moment.”

A year before Sandy received her diagnosis, Bev was found to have Stage 4 ovarian cancer. The sisters had discussed the fact that Oregon law allows people with terminal illnesses to take their own lives. Sandy now envied Bev’s situation. “I don’t think I have ever been as jealous about anything in my life as I am about this,” she wrote in her journal shortly after she saw Mapstone. It was weeks before she could get past that jealousy and take Bev into her confidence.

But even if Sandy had lived in Oregon, her Alzheimer’s disease would have precluded her from getting help in taking her own life. States that allow for assisted dying require two doctors to certify that the person has a prognosis of less than six months to live, and most people with Alzheimer’s have no such prognosis. They also require that the person be declared “of sound mind,” a difficult hurdle for someone whose brain is deteriorating.

On the phone that day, Sandy told Bev that pentobarbital was a controlled substance in the United States. She would have to write to one of the foreign suppliers listed in the book and hope for the best. Bev suggested an alternative: When the time came, she could request the drug from her own doctors in Oregon and then give it to Sandy. She didn’t think she would need it herself — her cancer seemed to be in remission, and all she really cared about was eventually dying without pain. Like almost everyone else in Sandy’s inner circle, Bev was devastated by the prospect of her sister’s decline and death, but she tried to tune out her own anticipatory grief so she could focus on helping Sandy die the way she wanted to.

On Dec. 9, 2012, Sandy’s daughter, Emily, and her partner, Julius Viksne, had a baby boy, whom they named Felix. Sandy went down to Austin, still able to make the familiar trip on her own. During the previous two years, her life had become more limited, but she continued to enjoy it. She spent time during Ithaca’s abbreviated growing season gardening in her backyard, either alone or in the company of Karen or Daryl’s sister, Robyn. Although she had abandoned writing in her journal, she could still read novels on her iPad, but nothing quite as complex as “The Road” anymore. She managed her day-to-day needs in part because she was such a creature of habit. She ate almost the same thing every day: a bagel for breakfast, a sandwich for lunch, a piece of salmon for dinner, mugs and mugs of tea throughout the day. Her freezer was always stuffed with 10-pound bags of almonds, so she could roast them by the handful and sprinkle a few onto chocolate frozen yogurt for her nightly treat. By then, she was also taking a second F.D.A.-­approved drug, Aricept, which inhibits the chemicals that break down acetylcholine, a neurotransmitter linked to short-term memory; people with Alzheimer’s often have lower concentrations of acetylcholine in their brains. Daryl wasn’t sure that either drug was making a difference. It was impossible to tell without knowing what Sandy would have been like without them.

Becoming a grandmother was never something Sandy had cared much about. But when Felix was born, she was thrilled. He was in the neonatal intensive-care unit when she arrived in Austin; doctors had detected a bacterial infection in his urine and were administering antibiotics. Sandy sat in a rocking chair alongside the bassinet, and Emily handed the infant to her, naked except for his diaper, the IV port in his tiny hand capped off until the next infusion. She gazed down at her grandson, placid and perfect. She cooed and babbled. For weeks afterward, she talked about those first moments holding Felix. “I don’t know what I was saying or what I was doing,” she would say. “But he just looked into my eyes.”

Emily was surprised to see her mother so at ease in the traditional role of Felix’s bubbe (Yiddish for “grandmother”). As a parent in the 1970s, Sandy turned every interaction with her children into a political act. During story time, she would go through their picture books with a bottle of Wite-­Out and a Magic Marker, changing a hero’s name from male to female, revising plot lines, adding long hair or breasts to some of the drawings. Story time was a different experience with Felix. Sandy would cuddle with the baby and turn pages. If she couldn’t remember the word for “zebra” or “lion,” she wouldn’t fuss about it. “Oh, it’s some animal,” she would say.

She told Emily that her “new brain” might actually make her better suited to being a grandmother than her focused, hyper­analytical “old brain.” She seemed to have found a way of being that she liked, content to sing silly songs and make nonsense sounds for hours on end.

Emily liked her mother this way, too. It had sometimes been difficult to be Sandy’s daughter. As a child, Emily wanted to wear her hair long and take ballet lessons; Sandy, ever vigilant about gender stereotypes, nudged her to cut her hair and play soccer instead. But now Sandy didn’t seem to care about such things. Emily thought that her mother was taking pleasure in life in a way that the old Sandy could not have anticipated — and she found herself hoping that the joy her mother took in Felix might make her reconsider her intention to end her life quite so soon.

The others in Sandy’s inner circle saw her relationship with Felix and wondered what it would mean for her original plan. The old Sandy, who valued her rationality and her agency, had been clear that she would be unwilling to keep living when she could no longer articulate coherent thoughts. But this newer Sandy didn’t seem unhappy living her life in this compromised way. Ultimately, who should make the decision to die, the old Sandy or the new one?

Ronald Dworkin, an influential legal scholar and the author of “Life’s Dominion: An Argument About Abortion, Euthanasia and Individual Freedom,” wrote about a kind of hierarchy of needs for people in Sandy’s situation, who want their autonomy to be respected even as disease changes the essence of who they are and what autonomy means. He differentiated between “critical interests” (personal goals and desires that make life worth living) and “experiential interests” (enjoying listening to music, for instance, or eating chocolate ice cream). Sandy was appreciating her experiential interests — playing with Felix and working in her garden — but her critical interests were far more sophisticated and were moving out of her reach. Critical interests should take priority when making end-­of-­life choices on behalf of someone whose changed state renders her less capable of deciding on her own, Dworkin wrote, because critical interests reflect your true identity. The new Sandy seemed to love being a grandmother, but it was important to take into account what the old Sandy would have wanted.

Granting priority to critical interests is difficult even in a society that tries to do so. In the Netherlands, the Termination of Life on Request and Assisted Suicide Act makes it possible for a doctor to end a person’s life when she is not cognitively able to do it herself, as long as she laid out her intention while she was still competent. According to the 2002 law, if someone with Alzheimer’s disease has an advance directive declaring her wish to die when her dementia reaches a point she considers intolerable — when she has to be spoon-­fed, for example, or put in diapers — that document is sufficient to allow a doctor to perform euthanasia. Nevertheless, it is rare for a doctor in the Netherlands to actually euthanize a patient who has dementia. In fact, one recent survey of 110 Dutch physicians treating dementia patients with advance directives asking to be euthanized found not a single one who had carried out the request. And of the 4,829 people who died in 2013 under the Dutch euthanasia act, just 97 of them, or 2 percent, had dementia.

“You know I plan to kill myself,” Sandy said all through 2013, whenever the thought occurred to her. She seemed to say it partly for the sake of others, so they could get used to the idea and steel themselves against pain and grief when the time came. But it seemed that it was also for her own sake, to keep her plan at the forefront of her disintegrating mind. Emily and Felix were living with Sandy at the time, so that Sandy could help with child care while Julius attended nursing school in Colorado. (Jeremy had recently moved out. He was going through a rocky time and was not communicating with the family, though he supported his mother’s plans.) It drove Emily crazy to hear her mother continually bring up suicide. “Stop saying that!” she would tell her.

One night in August 2013, when Sandy was home alone, she pulled out a yellow legal pad and sat down at the tile-­topped table in her big, oak-­trimmed kitchen, where she had eaten thousands of dinners. She had just heard of two experimental treatments for Alzheimer’s that she hoped might, in addition to the Namenda and Aricept, keep her functioning so that she could help care for Felix until August 2014, when Julius was scheduled to finish his nursing program and move back home. But the drugs were prohibitively expensive, and she would have to pay for them out of pocket, because her insurance wouldn’t cover the cost. On the pad, she started to make calculations. The treatment — a combination of IVIG (intravenous immunoglobulin), a drug approved for other neurodegenerative diseases, and repetitive TMS (transcranial magnetic stimulation), which was usually prescribed for depression — cost $6,000 every two weeks at the New York Memory and Healthy Aging Services. What if she could persuade the center to charge less, because at her size she would need less medication? And what if she received the treatment less frequently, maybe every three weeks? It was still a lot of money, but she had never touched her I.R.A., and she was already 69 and was clearly not going to live much longer. She calculated that her savings could cover about $4,000 every three weeks until Julius graduated in a year. At the bottom of the page filled with numbers, she wrote to remind herself not to fret too much over the staggering dollar amount. “Expensive: but now money is not an issue (because of imily).” The previously meticulous scholar had misspelled her daughter’s name.

Over the next months, Sandy and Daryl boarded a bus early in the morning every few weeks and rode down to Manhattan for the treatments. “I still feel as though I’m me,” she told him on one ride. “Do you agree?” He did, sort of. In fact, he was surprised by how much herself Sandy could still be, even as she became less and less the formidable thinker he had always known. He was surprised too to discover that it didn’t matter to him. “I realized how little of the fact that she was an intellectual played into my feelings for her,” he said. “They were feelings for her, not her intelligence. And they were still all there.”

Daryl proved himself steadfast, and as her more casual friends fell away, either because Sandy shut them out or because they were unwilling to witness her decline, he became more central to her life. He and Karen were the ones who saw her frequently, and they were the ones she kept checking in with to be sure her suicide window was not about to close.

In October, Sandy wrote to an address in Mexico listed on the website of “The Peaceful Pill Handbook.” Weeks passed, and she fretted that her order had been confiscated at the border. But at last it arrived: a cardboard box, no bigger than a softball, wrapped in brown paper. Sandy eagerly took scissors to the packaging and retrieved two 100-­milliliter bottles of pentobarbital — she had bought an extra one just in case, even though she believed that one bottle would be enough for a person her size. The drug needed to be kept in a cool place, so she took the bottles down to the basement. For the time being, she could leave the pentobarbital on a shelf, comforted by the knowledge that it was there.

Now that the matter of “How?” was taken care of, the Bems turned back to the elusive question of “When?” They still generally agreed that Sandy would probably be alive until the end of 2014. But even with the treatments in Manhattan, her cognitive deficits were becoming more pronounced. When Bev came from Oregon to visit, Sandy couldn’t understand how Bev and she could possibly have had the same parents. She didn’t recognize Robyn’s name in conversation, and when Emily tried to explain that Robyn was “Dad’s sister,” Sandy asked who, exactly, was Dad?

Daryl noticed something else disheartening. He had been following Sandy’s progress as she took up the piano again. The Bems had always had one in their home, though it was mostly for Daryl, who played and accompanied Emily, whose clear, resonant singing voice carried her through student productions and into a career in musical theater. Sandy had worked her way slowly and steadily through the lesson book, moving from the simplest “Twinkle, Twinkle” tunes to études that were slightly more complex.

Late in 2013, Daryl began to see that Sandy could teach herself to play up to a certain point in a piece, but the next time she sat down at the piano she had to flip back several pages and work her way up all over again. A few months later, whenever she sat down and flipped back several pages, she could make it only part of the way to where she had been the last time she played. And a few months after that, she would sit down at the piano, flip back to the beginning and get stuck at “Twinkle, Twinkle.”

Even that was O.K., Daryl thought. She seemed to be enjoying whatever it was she could play. And then one day, she didn’t even have that. Even the easiest pieces had become too difficult. Almost simultaneously, she was no longer able to read novels on her iPad or follow movie plots with complex flashbacks. Eventually there were only two movies she enjoyed: “Mary Poppins” and “Funny Girl.”

Right around Christmas, Julius dropped out of nursing school and rejoined his family. Sandy no longer felt it made sense to spend thousands of dollars in the hope of staying a little more functional a bit longer for Felix’s sake. She told Daryl she wanted to stop the treatments. Shortly afterward, over dinner in her kitchen, she told him something else: She wanted to talk about when might be a good date to die.

O.K., Daryl said mildly, trying to stay focused on the task at hand, pre-­emptively shutting down thoughts about what it would really mean to lose her. How about June? He knew how much Sandy would want to get back to her garden when the dreary Ithaca winter finally ended, and he hoped this would be a way to make her last few months happy ones. She agreed that June sounded right.

At the time, Emily, who was splitting time between her mother’s house and her own home, was back in Austin. She and Julius were planning to buy a house a few miles beyond the Ithaca city limits, and she was preparing for the move. One day in April, Emily returned to Ithaca and was driving home from a bank with her father, who was helping her secure a mortgage. She was at the wheel of Sandy’s car.

Should we change the car registration and put it in your name? Daryl asked. Emily started talking about wanting to wait until late summer, when she would be in her new house and would need to change the address only once. Maybe in July she could ask Sandy to sign over the car to her.

“Oh, she’ll be dead by June,” Daryl said.

Emily struggled to keep the car on the road. “What did you just say?”

Daryl looked at her, surprised by her surprise. He assumed Sandy had talked to Emily. But she hadn’t, and Emily thought June was much too soon. She was looking forward to the summer with her mother and her son — Felix running around his bubbe’s backyard in the late afternoon light while Sandy puttered in the garden, digging a hole here, moving a rose bush there, pulling up weeds around the lilacs.

Emily was angry at her father for speaking so pragmatically about her mother’s death. She was angry too at her mother for choosing a date that was so soon, and at her mother’s inner circle for allowing all of it to happen. That night, she sat with her parents and Robyn while they discussed the situation. Emily felt as though she was defending her mother’s life against everyone who wanted her to end it.

“You’re just doing the math,” she told Daryl. “It’s like you’re just calculating: Judging by the rate of decline of X amount, you can predict that by time Y this will be the case. But you can’t!”

“O.K., so maybe not June,” Daryl said, backing off. He had spent his life avoiding conflict. “We just thought that with your mother turning 70 on June 22, that might be a good time.”

“Well, that’s nuts,” Emily said. “How can you just pick a month like that?”

“What month did we say, again?” Sandy asked.

“June,” Daryl said.

“Why don’t you just say August?” Emily said. “It could just as easily be August as June.”

“What month did we say, again?” Sandy asked.

“June,” Daryl said.

“August, June — you can’t just draw an equation,” Emily said.

“What month did we say, again?” Sandy asked.

Emily turned to her mother. “You slogged through the winter,” Emily told her. “By late May, it will be gorgeous around here.” She wanted Sandy to hold out for one more summer. She wanted Sandy to want to hold out.

“I’m sure it would be nice,” Sandy agreed. But her voice was flat; the prospect of one more summer, even with Emily, even with Felix, even with her garden, no longer seemed to be enough.

The nagging sense that there might be more time, that there should be more time, is inevitable for those close to a person with dementia who wants to end her life. At an annual conference in Chicago last summer of the World Federation of Right to Die Societies, a collection of 51 member organizations that push for right-­to-­die laws in 23 countries, the problem of timing was a running theme.

One night in April when Daryl was over for dinner, Sandy said to him out of the blue, “You’re so smart.”

I haven’t read all the comments, so forgive me if this has been mentioned. I am shocked that someone who knew they were failing mentally…

“Is that it, or is it that as you get dumber, I feel smarter to you?” Daryl asked with a smile, taking a risk that Sandy still retained her puckish sense of humor.

She laughed. “I guess that’s it,” she said.

But she told him that she could feel herself slipping and that the day of her death would need to be “sooner rather than later.” Daryl pulled the 2014 calendar down from the kitchen wall. He chose a date. How about Tuesday, May 20?

Sandy agreed, and Daryl wrote it down. She told Karen, Bev and Robyn what she had decided. She planned to tell Emily but wanted to do it in person when her daughter returned from Austin. Emily and Felix arrived in Ithaca on May 13, and her parents told her that Sandy would die the following Tuesday. Emily was appalled. Just one week from today? She was sure it was much too soon.

That evening, she sat with her parents on the big L-shaped white couch in Sandy’s oversize living room, the site of many serious family conversations over the years. Bev, Karen and Robyn were there as well. Emily had no problem with the general idea of Sandy’s ending her life soon, she said angrily, but now? Now? Karen and Robyn tried to explain how deeply changed Sandy was: She rarely laughed and seemed to find little joy in people or experiences. Emily thought everyone was thinking too narrowly. They assumed that her mother’s joylessness was a result of the encroaching disease. Emily saw it as depression. The neurologist had recently taken Sandy off Prozac and started her on Zyprexa, an antipsychotic. Maybe her dose should be adjusted. Or the doctor should prescribe a different drug. Emily felt that they all needed more time to sort out what was causing Sandy’s change of mood.

As the weekend approached, there was another discussion on the big white couch. Karen and Robyn wanted to make it clear to Emily how much Sandy had declined in the month she was away. “You didn’t see this moment, Em,” Robyn said, “when your mom was standing in the kitchen. She looked a bit lost and turned to me and said: ‘I’m hungry. What do I do when I’m hungry?’ ”

And just the other day, Robyn went on, Emily had been chatting in the kitchen with her mother and Bev. After Emily walked out, Sandy turned to Bev and asked, “Who is that person’s mother?”

“You are,” Bev said, trying not to cry.

“I thought so,” Sandy said. ”I thought it might be me.”

Emily now understood that Sandy was deteriorating rapidly. Karen organized a small gathering on Sunday, May 18, to celebrate Sandy’s life. It was very intimate, just Sandy, Daryl, Emily, Karen, Bev and Robyn. (Jeremy had moved out West and still wasn’t in contact with his family, though Sandy and Daryl left a voice mail message to let him know when Sandy would die.)

At the gathering, Daryl ­talked about a lawsuit that the Equal Employment Opportunity Commission filed in 1972 against AT&T for sex discrimination in its recruitment practices, in which he and Sandy took the stand together to testify as a team.

“Did I really do that?” Sandy asked, pleased.

He talked about her expert testimony in another lawsuit, filed by the National Organization for Women against The Pittsburgh Press, that went all the way to the Supreme Court in 1973 and made it illegal to categorize classified job listings by gender.

“Did I really do that?” Sandy asked again.

Karen talked about how, relatively late in life, Sandy decided to go back to school at Rutgers and get a doctor of psychology degree while still teaching part ­time at Cornell. In 2000, at 56, she opened a psychotherapy practice, turning the den in her house into an office that she made comfortable with big pillows. Emily said her mother had always been fearless and had raised her and her brother to always think for themselves.

The next day was warm and sunny, so a small family entourage went to Stewart Park, on the shores of Cayuga Lake, for what they all knew would be a final outing. Julius pushed Felix in a stroller, with Bev and her partner alongside them; Emily walked behind, holding her mother’s hand — something she hadn’t done since she was a child. When they all stopped at the playground to let Felix run around, Emily pulled Sandy over to sit with her on a bench nearby.

Emily said she understood why her mother felt she needed to take her life now. She spoke admiringly of Sandy’s ability to find exactly the right moment — not too early, not too late. “I think you nailed it,” she said. Sandy was quiet while Emily spoke, looking into her eyes. Her relief was deep and obvious, but all she said before they hugged was, “I’m so glad.”

On her last day, five years after she first went to see Mapstone, Sandy set about creating a tidy paper trail to make sure no one else would be held responsible for her death. She found the printout of an email, with the subject line “ENDING,” that she sent to Daryl nine months earlier, stating why she wanted to die and saying that no one — not her physician, not her attorney, not anyone — had offered help or advice. In the email, she had written that she would add the date of her death, “and perhaps other thoughts,” when the time came, another way to make it plain that her death was her decision alone.

When the time did come, there were really no other thoughts. All the ideas Sandy might have wanted to express in writing — the sophisticated musings, the incisive arguments, the upending of conventional thinking — were already beyond her. Sandy sat down with the printout of the “ENDING” email and in longhand wrote out the date, May 20, 2014, the one she had been repeating to herself ever since Daryl wrote it on the calendar. She followed it with a simple declaration: “The time has come to end my life. I love you, Daryl.” She signed it, formally, Sandra L. Bem. Then she and Daryl went for a walk in the Fall Creek Gorge, a ruggedly beautiful spot, 110 stone steps down from the noise of Stewart Avenue.

When they got back, Sandy and Daryl watched “Mary Poppins.” Emily, Bev and their partners had assembled at Karen’s house. Karen wanted Sandy to feel as if “a loving net was around her” as she prepared to die — though it had to be love at a distance, because Sandy wanted no one but Daryl in the room.

Around 5:30 p.m., Sandy took anti-nausea medicine and poured herself a glass of wine; she had read that drinking alcohol after taking the pentobarbital would mask its bitter taste and speed its action. With Daryl accompanying her, she carried the glass of wine upstairs to her bedroom and set it on the night stand. Next she had to trim the foil off the collar of the 100-­milliliter vial of pentobarbital using manicure scissors and remove the small rubber stopper. Daryl held his breath, unsure whether Sandy could manage all these maneuvers on her own. She did. She poured the pentobarbital into a glass and set it next to the wineglass.

“Now what?” she asked. Daryl didn’t know what to say. They had expected the preparations to take an hour or so, yet just 15 minutes had passed.

“Have you decided what to wear?” he asked. She said she was happy with what she already had on. She got into bed and looked at the two glasses on the night stand. She asked which was the drug and which was the wine.

“The drug is clear, and the wine is red,” Daryl said.

Sandy nodded and looked around the room and then at the two glasses again. She asked which was the drug and which was the wine. Daryl told her again.

“Can I sip some of the drug and then drink some of the wine?” Sandy asked. “That’s not a good idea,” Daryl said. “You don’t want to fall asleep before you’ve drunk it all.”

“O.K., I’ll drink the whole thing,” she said, and she did. He asked if it tasted terrible. “No,” she said. “It’s intense, but it’s not bitter. I’m not having any problem with it.”

She put the glass down. “How much wine am I supposed to drink?” she asked. Daryl told her she could have as much as she wanted. She took a sip.

“I have to go pee,” she said.

“You can’t go pee,” Daryl said. “I’m afraid you’ll fall asleep.”

“Can you come with me?” she asked.

So Daryl and Sandy walked to the bathroom together, and Daryl sat outside the door while his dying wife sat on the toilet.

He helped Sandy back into bed, and within five minutes she was unconscious. Daryl watched her for a while, not quite feeling anything. Still to come were the calls to 911 and the coroner and the undertaker, and the writing up of the death notice, highlighting the reasons for Sandy’s decision. Still to come, too, was the brutal reality of what it would feel like for Sandy to be completely gone from his life. “How powerful a presence is her absence,” Daryl would say at a memorial service that summer, quoting from a poem by Fred Chappell. “The rooms were quiet when she was resident./Now they lie silent. That is different.”

For now, though, Daryl simply gazed at his unconscious wife. Around 8:30, he telephoned Bev at Karen’s house around the corner. Bev came over to sit with him at Sandy’s bedside. They were quiet, watching the sheet go up and down with each breath. Over the next hour, the sheet’s rise and fall began to slow. Then it stopped.